/*-
 * Copyright (c) 2004-2005 David Schultz <das@FreeBSD.ORG>
 * Copyright (c) 2023-2024 Haiku, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef _FENV_H_
#define _FENV_H_

#include <stdint.h>
#include <sys/cdefs.h>
#include <sys/types.h>

#ifndef __fenv_static
#define __fenv_static static
#endif

typedef uint32_t fenv_t;
typedef uint32_t fexcept_t;

/* Exception flags */
#define FE_INVALID 0x0010
#define FE_DIVBYZERO 0x0008
#define FE_OVERFLOW 0x0004
#define FE_UNDERFLOW 0x0002
#define FE_INEXACT 0x0001
#define FE_ALL_EXCEPT (FE_DIVBYZERO | FE_INEXACT | \
                       FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW)

/*
 * LoongArch Rounding modes
 */
#define _ROUND_SHIFT 8
#define FE_TONEAREST (0x00 << _ROUND_SHIFT)
#define FE_TOWARDZERO (0x01 << _ROUND_SHIFT)
#define FE_DOWNWARD (0x02 << _ROUND_SHIFT)
#define FE_UPWARD (0x03 << _ROUND_SHIFT)
#define _ROUND_MASK (FE_TONEAREST | FE_DOWNWARD | \
                     FE_UPWARD | FE_TOWARDZERO)

__BEGIN_DECLS

/* Default floating-point environment */
extern const fenv_t __fe_dfl_env;
#define FE_DFL_ENV (&__fe_dfl_env)

#define __rfs(__fcsr) __asm __volatile("movfcsr2gr %0, $r0" : "=r"(__fcsr))
#define __wfs(__fcsr) __asm __volatile("movgr2fcsr $r0, %0" ::"r"(__fcsr))

__fenv_static inline int
feclearexcept(int __excepts)
{
    fexcept_t __fcsr;

    __rfs(__fcsr);
    __fcsr &= ~__excepts;
    __wfs(__fcsr);

    return (0);
}

__fenv_static inline int
fegetexceptflag(fexcept_t *__flagp, int __excepts)
{
    fexcept_t __fcsr;

    __rfs(__fcsr);
    *__flagp = __fcsr & __excepts;

    return (0);
}

__fenv_static inline int
fesetexceptflag(const fexcept_t *__flagp, int __excepts)
{
    fexcept_t __fcsr;

    __rfs(__fcsr);
    __fcsr &= ~__excepts;
    __fcsr |= *__flagp & __excepts;
    __wfs(__fcsr);

    return (0);
}

__fenv_static inline int
feraiseexcept(int __excepts)
{
    fexcept_t __fcsr;

    __rfs(__fcsr);
    __fcsr |= __excepts;
    __wfs(__fcsr);

    return (0);
}

__fenv_static inline int
fetestexcept(int __excepts)
{
    fexcept_t __fcsr;

    __rfs(__fcsr);

    return (__fcsr & __excepts);
}

__fenv_static inline int
fegetround(void)
{
    fexcept_t __fcsr;

    __rfs(__fcsr);

    return (__fcsr & _ROUND_MASK);
}

__fenv_static inline int
fesetround(int __round)
{
    fexcept_t __fcsr;

    if (__round & ~_ROUND_MASK)
        return (-1);

    __rfs(__fcsr);
    __fcsr &= ~_ROUND_MASK;
    __fcsr |= __round;
    __wfs(__fcsr);

    return (0);
}

__fenv_static inline int
fegetenv(fenv_t *__envp)
{
    __rfs(*__envp);

    return (0);
}

__fenv_static inline int
feholdexcept(fenv_t *__envp)
{
    __rfs(*__envp);
    *__envp &= ~FE_ALL_EXCEPT;
    __wfs(*__envp);

    return (0);
}

__fenv_static inline int
fesetenv(const fenv_t *__envp)
{
    __wfs(*__envp);

    return (0);
}

__fenv_static inline int
feupdateenv(const fenv_t *__envp)
{
    fexcept_t __fcsr;

    __rfs(__fcsr);
    __wfs(*__envp);
    __fcsr &= FE_ALL_EXCEPT;
    feraiseexcept(__fcsr);

    return (0);
}

#if __BSD_VISIBLE

int feenableexcept(int __mask);
int fedisableexcept(int __mask);
int fegetexcept(void);

#endif /* __BSD_VISIBLE */

__END_DECLS

#endif /* _FENV_H_ */